Grinding machine



June '13, 1945. R H, HUTCHlNsGN 2,42,225

GRINDING MACHINE Filed April 16, 1945 2 Sheets-Sheet l v INVENTO/Q. PHIL/P H HUTCHINSON H/sATTo/aA/EY.

Junk 1%, W46.

P. H. HUTCHINSON GRINDING MACHINE Filed April 16, 1945 2 Sheets-Sheet 2 HLJTCH/NSON T TO RN E1.

2 INVEN Toe.- PHILIP H.

Patented June 18, 1946 UNITED STATES PATENT OFFICE GRINDING MACHINE Philip H. Hutchinson, Montclair, N. J., assignor to General Motors Corporation, Detroit, MiclL, a corporation of Delaware Application April 16, 1945, Serial No. 588,465

This invention relates to grinding machines and comprises all of .the features of novelty herein disclosed, An object of the invention is to provide an improved machine for grinding convexly rounded surfaces onthe ends of elongated articles. Another object is to provide a centerless grinding machine for automatically grinding, on the opposite ends of tappet pins, cylindrical rollers, or the like, spherical segments which have a common center of curvature at the geometric center of the article.

To these ends and'also to improve generally upon devices of this character, the invention consists in the various matters hereinafter described and claimed. In its broader aspects, the invention is not necessarily limited to the specific construction selected'for illustrative purposes in the accompanying drawings in which Fig. 1 is a plan view of the machine, partly in section.

Fig. 2 is a front view, the grinding wheel being in section and the discharge mechanism bein omitted.

Fig. 3 is an end view of a post and associated parts. l V

Fig. 4 is an end view, broken away, of some details.

Fig. 5 is aperspective view of a blade and a portion of its supporting lever.

Fig. 6 is a detail view of the post.

Fig. '7 is a plan view of loading and discharging mechanisms.

Fig. 8 is a perspective view of parts appearing in Fig. 7.

Fig. 9 is a front view of Fig. 7 with parts in section.

Fig. 10 is a front View nism.

Fig. 11 is a front view of loading mechanism.

Fig. 12 is a view similar to a portion of Fig. 1 with the parts in a different position, this View showing four possible positions of a work piece.

Fig. 13 is a perspective view of a Work piece in perative relation to the grinding wheel.

Fig. 14 is a view similar to Fig. 13 with parts added.

Fig; 15 is a view similar to Fig. 14 with the post added.

Fig. 16 is a front view of a detent.

Fig. 17 is a perspective view of the discharge block.

The work piece W is herein illustrated as a cylindrical pin or roller whose convexly rounded ends are to be ground as spherical segments which lie in the surface of a. common sphere.

of discharging mecha- 1 Claims. (01. 51-103) whose center is at the geometric centerof the pin. Th e'endsof the pin eng ge a pair of spaced arcuate surfaces 2 on opposite sides of a groove in the periphery of a grinding wheel G while the pin is supported for rotation by peripheral contact with a regulating wheel 4 and a flat Si l porting blade 6 which .enters the groove. When ingrinding position the geometric center of the pin is also the common center of the arcuate abrasive surfaces. The blade 5 a hardened insert fixed in an inclined position at the slapped off top, of a vertical post 8. I'i 1e post is generally cylindrical and has a supporting flange [0 resting on an arm I 2 prOJ'Ecting laterally between the wheels from a bracket IZA which has a remote leg I2B projecting laterally away from the wheels and fastened to the end of a slide M which supports the regulating wheel. The .post is angularly adjustable. as by a pin 16 projecting from its flange I0 between a pair ofadjusting screws l8 carried by lugs 20 on the arm 12. This is to place" the plane of the blade 6 exactly parallel to an element of the regulating wheel when the Work is cylindrical. To hold the post clamped in adjusted position, it is extended downwardly into a hole 2| of the m I? Whe e a o ve .22 wi one side tapered is engaged by a cone-pointed clamping screw 24., a

To insure uniform rotation of the work and to avoid displacement of the .work which might otherwise occur due to the narrow areas of contact with the grindi Wheel, the work is also engaged and supported by a second inclined blade 26 formed as a hardened insert at the upper end of lever 28 whose upper portion occupies the groove in the grinding wheel (or the space between a pair of grinding wheels) the lever being pivoted at 30 to lugs on the'arm [2. The blade is urged to work engaging position by a spring 32 housed in the lower end of the post and engaging a horizontal lever arm which has a cam surface 34 adapted to ride on the hump of a rib 36 projecting upwardly from the center of a slotted plate as which is adiustably fastened by screws to a base plate 40. The slotted plate has a tongue guided in a groove M of the base plate. In the grinding position, the spring urges the blade 26 downwardly and laterally against the work, the blade being bevelled slightly in opposite directions from the, center to form a ridge having a central .point of contact with the work so as not to interfere withcontrol of the location of the .workby the regulating wheel and the supporting blade 6., The axis of the work is maintained parallel tothe axis of the grinding wheel and preferably below a line connecting the wheel centers, When the regulating wheel slide and the attached elements are retracted from the grinding wheel as will appear, the cam 35 rides on the fixed rib 36 and swings the blade 26 away from the work to facilitate loading of a new piece and discharge of a ground piece.

The base plate 40 is fastened to an oscillating head or column 42 whose axis of oscillation in the vertical line A in Fig. 2 passes through the center of the post 8 and through the geometric center of the work when the latter is in grinding position. Any suitable means is used to-oscillate the head through a small angle so that the arcuate wheel surfaces 2 are kept dressed by the work to the proper arcuate shape. The arcuate surfaces 2 have their common center of curvature in the axis of oscillation. The oscillating head has a projecting arm 44 provided with a bearin housing 45 in which a cam shaft 46 having a cam 48 is journalled for rotation, Ihe cam shaft is driven by a ulley 50 and a belt 52 from a pulley 54 mounted loosely on the shaft which drives the regulating wheel. An idler pulley 56 on a spring pressed arm 58 engages the belt. The cam 48 engages a cam follower roll 60 journalled on a cam slide or carrier 62 which has a slideway 53 on the arm 44. A coil spring 64 urges the roll 60 against the cam which is designed to cause reciprocation of the slide with a long dwell in advanced position and a short dwell in retracted position. The regulating wheel slide I4 is adjustably secured by a screw 66 to the cam slide or carrier and moves therewith.

The work pieces are supplied to the machine and discharged therefrom one at a time. They are urged endwlse in a stream by gravity or otherwise through a feed tube M whose exit end is fastened by a set screw in a loading block I6 which is internally round and externally rectangular. The block is fastened by screws in a shallow groove at the top of a holder 80 which is T- shaped, a vertical shank 82 on the holder being slotted and adjustably clamped by screws to a horizontal arm 83 projecting forwardly at the top of a loading bracket 84 whose base 86 is slotted and adjustably secured to the base plate 40. A locating tongue on the base 86 enters a slot 83 in the base plate. When the parts are in grinding position as shown in Fig. 1, a detent or separator 9D lies across or covers the loading block opening to retain the supply of work pieces. The detent comprises a horizontal arm or blade on a slotted vertical leg 92 adjustably secured by screws in a groove of a vertical arm 94 of an angular bracket 96 which has a slotted base 98 adjustably secured on the bracket I2A. When the slides and the parts supported thereby are retracted, the detent is retracted as indicated in Fig. 12 together with the ground piece, and the new piece, urged forward from the feed tube, pushes the ground piece axially against an adjustable stop screw I while the next advance of the slide which carries the new piece to grinding position causes discharge of the ground piece as will appear. The ground piece which engages the stop screw locates the new piece endwise with its center opposite the middle of the grinding wheel and so the piece engages both'abrasive surfaces evenly. The stop screw Hill is in. axial alignment with the bore of the loading block and is threaded in the thicker and more remote end of a discharge block I02, the thinner end of the block having a rounded recess I04 at one side to partly encirclethe ground piece. The block I02 is adjustably secured by screws in a horizontal groove in the front of a discharge bracket I08 which has a base IIU adjustably fastened to the base plate 40 and provided with a tongue H2 enterin a guiding and locating groove. Welded to the bracket below the dischargeblock is an inclineddischarge chute H4.

The ground piece is temporarily retained in the recess Ill l by a vertical retaining plate Iii welded to the vertical edge of a bent lever I I8 whose hub is pivoted at I20 to the top of the bracket I08. A coil spring I22 secured to the lever and passing through a notch in the bracket is anchored to a bent pin I24 on the bracket and urges the retaining plate toward the ground piece, a stop pin I 26 serving to limit such move ment. To swing the retaining plate away from the ground piece and thus drop the latter into the discharge chute, the lever is actuated on advance of the slide. For this purpose, an upright arm I28 of the lever I I8 lies in the ath of an actuating pin I30 on a horizontal slotted bar I32 which is clamped by a screw to the upper end of an angle bracket I34 whose lower horizontal arm I35 projects laterally and is fastened to the end of the cam slide or carrier 52.

In operation, the work is rotated by the regulating wheel while in supported position between the blades 6 and 26 and While the arcuate surfaces 2 on th grinding wheel generate spherical segments even in the absence of any oscillation. The speeds and directions of rotation are those which are usual in centerless grinders. If oscillation is deemed desirable, all parts except the grinding wheel partake of such movement. Whenever the slides are retracted by the cam action, there will be a ground piece engaging the stop screw I00 in the discharge block where it has been pushed by a new piece moving axially to supported position on the blade 6 and the regulating wheel, the upper blade 26 then being retracted. The surplus pieces in the loading block will be retained temporarily by the new piece. As

th slides advance, the detent 99 will take over the holding of the surplus pieces in the feed block while the new piece advances to grinding position. Also the upper blade 26 wil1 Swing in against the new piece. As the bar I32 advances, the lever arm I 28.0f lever H8 is actuated to cause retraction of the retaining plate H6 from the side of the previously ground piece in the discharge block whereupon that piece falls into the discharge chute. Upon subsequent retraction of the slides. the newly ground piece is carried into line with the loading block and the discharge block just as the detent 9i] releases a new piece which thereupon moves axially to supported position as it e pushes the newly ground piece against the stop driven abrasive member having a pair of spaced arcuate surfaces, mechanism for supporting and rotating a round work piece with its ends in contact with the arcuate surfaces and with its axis passin through the common center of the arcuate surfaces, and an oscillating support for said mechanism, the axis of oscillation passing through said common center.

3. In a machine of the character indicated, a rotatable grinding wheel having a groove in its peripher and opposed arcuate surfaces at the sides of the groove, and mechanism for supporting and rotating a round work piece with its axis parallel to the wheel axis and with its ends in contact with the arcuate surfaces,

4. In a machine of the character indicated, a rotatable grinding wheel having a groove in its periphery and opposed arcuate surfaces at the sides of the groove, mechanism for supporting and rotating a round work piece with its axis parallel to the wheel axis, and means for causing a relative movement of approach between the wheel and the supporting mechanism to bring the ends of the work piece into contact with the arcuate surfaces.

5. In a machine of the character indicated, a rotatable grinding wheel having a groove in its periphery and opposed arcuate surfaces at the sides of the groove, mechanism for supporting and rotating around work piece with its axis parallel to the wheel axis, means for delivering the work piece endwise onto the work supporting mechanism with its geometric center in line with the center of the groove, and means for advancing the work piece sideways towards the wheel to bring its ends into contact with the arcuate surfaces.

6. In a machine of the character indicated, a rotatable grinding wheel having a pair of spaced arcuate surfaces, a regulating wheel and a work blade for supporting and rotating a round work piece with its ends exposed, and means for causing a relative movement of approach between the grinding wheel on the one hand and the regulating wheel and blade upon the other hand to cause the geometric center of the work to be located at the center of curvature of the arcuate surfaces.

7. In a machine of the character indicated, a rotatable grinding wheel having a pair of spaced arcuate surfaces, mechanism for supporting a round work piece and rotating it on its axis with its ends exposed, and means for moving relatively to one another the wheel and the supportin mechanism to locate the work with its axis in a line passing through the common center of our- Vature of the arcuate surfaces.

8. In a machine of the character indicated, a rotatable grinding wheel having a pair of spaced arcuate surfaces, mechanism for supporting a round work piece and rotating it upon its axis with its ends exposed, and carrier for effecting relative movement between the wheel and said mechanism to bring the end faces of the work and the arcuate wheel surfaces into contact while the axis of the piece is maintained parallel to the wheel axis.

9. In a machine of the character indicated, a rotatable grinding wheel having a groove in its periphery and opposed arcuate surfaces at the sides of the groove, and mechanism for supporting and rotating a round work piece with its ends in contact with the arcuate surfaces, said mechanismcomprising a regulating wheel opposed to the grinding wheel and a work blade located in the groove.

10. In a machine of the character indicated, a rotatable grinding wheel having a groove in its periphery and opposed abrasive surfaces at the sides of the groove, work supporting and rotating mechanism, and a spring pressed blade mounted 6 within the groove to move towards or from the work.

11. In a machine of the character indicated, a rotatable grinding wheel having a groove in its periphery and opposed abrasive surfaces at the sides of the groove, a regulating wheel and a work blade for supporting and rotating a round Work iece with its ends in contact with the abrasive surfaces, and a second work blade located in the groove and yieldably urged against the work.

12. In a machine of the character indicated, a

rotatable grinding wheel having a groove in its periphery andopposed abrasive surfaces at the sides of the groove, a regulated wheel opposed to the grinding wheel, and a pair of work blades mounted within the groove and cooperating with the regulating wheel to support the work with its ends in contact with the abrasive surfaces,

13. In a machine of the character indicated, a grinding wheel, a carrier shiftable towards or from the grinding wheel, work supporting mechanism mounted on the carrier, 2. work blade having a pivotal mounting on the carrier, means actuated by the shifting of the carrier for causing the blade to engage or release the work, and means for advancing a work piece onto the Work supporting mechanism when the blade releases a preceding piece.

14. In a machine of the character indicated, a grinding wheel, work supporting and rotating mechanism, a carrier for shifting said mechanism towards or from the grinding wheel, mechanism responsive to retreat of the carrier for moving an elongated work piece endwise onto the work supporting and rotating mechanism, a discharge block in line with aid work piece to receive a preceding piece removed by advance of the first mentioned piece, and means for causing said preceding piece to locate the first mentioned piece opposite the grinding wheel.

15. In a machine of the character indicated, a grinding wheel, Work supporting and rotating mechanism, a carrier for shifting said mechanism towards or from the grinding wheel, mechanism responsive to retreat of the carrier for moving an elongated work piece endwise onto the work supporting and rotating mechanism, a discharge block in line with aid work piece to receive a preceding piece removed by advance of the first mentioned piece, a retaining plate adjacent to the discharge block, and means actuated by advance of the carrier to retract the retaining plate and discharge the preceding piece.

16. In a machine of the character indicated, a grinding wheel, work supporting and rotating mechanism, a carrier for shifting said mechanism towards or from the grinding wheel, a discharge block in line with the retracted position of a Work piece and having an open-sided recess to receive a ground piece, a retaining plate at the open side of the recess to retain the ground piece while the carrier i retracted, and means actuated by advance of the carrier to move the retaining plate away from the recess.

17. In a machine of the character indicated, a grinding wheel, work supporting and rotating mechanism, a carrier for shifting said mechanism towards or from the grinding wheel, a loading device opening to one side of the Work supporting mechanism, and a detent mounted on the carrier to uncover the opening when the carrier is retracted.

18. In a machine of the character indicated, a grinding wheel, work supporting and rotating mechanism, a carrier for shifting said mechanism towards or from the the grinding wheel, a loading device opening to one side of the Work supporting mechanism, a discharge block in line with the loading device, a detent actuated by retreat of the carrier touncover the opening for passage of an unground work piece, and a retaining plate actuated by advance of the carrier to release a previously ground piece from the discharge block when the unground piece is carried to grinding position.

a 19. In a machine of the character indicated, a grinding 'wheel, a regulating wheel and a work blade for supporting and rotating a round Work piece, a second work blade yieldably urging the piece against the regulating wheel and the first mentioned blade; the second work blade being bevelled to have a central point of contact with the piece.

20. In a machine of the character indicated, a grinding wheel, a regulating wheel, a post mounted to swivel with respect to said wheels, an inclined work blade on said post to support a work piece in contact with the regulating wheel, and a second work blade overlying said post and spring pressed against the piece.

21. In a machine of the character indicated, a grinding wheel, a slide shiftable towards or from the grinding wheel, a regulating wheel and a work blade mounted on the slide for supporting and rotating a round work piece, an oscillating support for the slide, and means for reciprocating the slide to move the work piece into and out of the axis of oscillation with a dwell in the advanced position.

PHILIP H. HUTCHINSON. 

